Lawrence v



Patented Aug. 25, 1925.

UNITED s'rn'rss PATENT OFFICE.

LAWRENCE V. REDHAN AND HAROLD OF CHICAGO, TLLIKOIB, AB-

SIGNORS TO BAKELITE CORPORATION, 01' YORK, N .,Y., A CORPORATION 01DELAWARE.

- PAPER No Drawing.

To all whom it may concern:

Be it known that we, (1) LAwRnNcn V. REDMAN and (2) HAROLD G. CHEETHAM,citizens of the United States, residing at 5 (1) Chicago, 22' Chicago,in the Count of (1) Cook, 2 Cook, and State of Illinois, (2) Illinois,have invented certain new and useful Improvements in Paper Products andProcesses of Making the Same, of which the following is a speclfication.

This invention relates to paper or aperlike products (card-board,pulp-boar composite or. laminated phenolic resin. Products of thisgeneral nature have been heretofore made, as d1'sclosed in the U. S.patents to Baekeland Nos. 1,160,362 and 1,160,365, by beating togetherthe fiber in water suspenslon, and

90 either phenols and formaldehyde, or equivalent substances, .or theirinitial react on products. The present invention comprises an improvedprocess of this general type, and the improved product resultingtherefrom.

According to the present invention in its preferred embodiment, thefiber in water suspension is beaten, for example in par-beaters, orother 80 mg engine, with amixture comprising as its essential componentsa phenol resin of the so-called permanently fusible and soluble tyotherwise known as a non-reactive p enol resin, a methylene-containinghardening agent, preferably hexamethylenetetramine; and a, free phenolicbody. For the best results it is necessary to o serve certainprecautions as to the proportioning' of these several components; al-

though as will appear hereinafter, there exist an indefinite number ofproportions conforming to. these general requirements, and theplasticity of the product can be varied at will to conform to specialrequirements.

The phenol resins, as preferably employed for the'purposes of thisinventlon, are of the hard, brittle,'easily pulverizable nonreactivetype, containing a greater or less proportion of free phenol. It isessential for securing the most desirable plasticity in the product thatthis free phenol should be retamed by the resin during the beatingoperation. Water however will quickly products etc. etc.) comprisingorganic or inorganic fibers and a suitable type'of beatrnonucr ANDraocnss or untrue 'rnn sum Application fled rams, 192:. Serial no.ceases.

eliminate free'phenol from the finely powdered resin and this reason weadd to the water in the beater sufiicient free phenol to effect itssubstantial saturation, thereby preven-ting it from extracting freephenol from the resin. From 5 to 8 ercent of phenol or less, based onthe weight of the water, will usuall suflice, the amount varying ofcourse wit the temperature, with the articular kind of henol or cresolemploye etc. The hardening agent,

which is preferably hexamethylenetetramine, is used in suflicient proortion to unite with and harden the fusible resin, forming therewith inthe first instance a potentially reactive composition; and in suflicientexcess of such proportion to react with the phenol present in the resinand in the water, forming with this phenol .either a non-reactive resinor a potentially reactive resin, according to the particular propertiesdesired in the product, in. which the non-reactive resin, if present, iscapable of acting as a plasticizer.

A typical formula, to which however the invention is not limited,comprises 450 lbs. non-reactive phenol resin.

500 lbs. cotton or paper pulp.

7500 lbs. water.

375 lbs. commercial phenol.

240 lbs. hexamethylenetetramine.

The resin is first finely powdered, preferably to pass 100 mesh. Thefiber ma advantageously be a mixture of cotton floc and sulfite pulp,although any suitable fiber or fiber-mixture, including asbestos, may beused. The hexamethylenetetramine may be substituted wholly or in part byan equivalent proportion of formaldehyde or other aldehyde capable ofhardening the resin and of reacting with the phenol. Other phenolicbodies may of course replace phenol. We preferably add also in thebeater a small proportion of any suitable release material or lubricant,preferably calcium stearatc in powdered form.

The whole mass is now beaten to. a homo geneous pulp after the manner ofmaking paper and is then run onto the screens, ap-

plying such vacuum as will leave in the wet paper approximately onepound of wator for each pound of dry paper.

per may then be dried either by runnlng through warm calendering rollsor by pass-' The paing through a dr ing oven, care being taken in eithercase t at the chemical reaction between the phenol resin, the phenol,and the hexamethylenetetramine or formaldehyde does not then proceed tothe final reaction stage, but that the resin content of the paperremains potentially reactive. When the paper is used for making alaminated product, as described below, the final reaction occurs duringthe hot-pressure consolidation of the laminae.

The paper may be prepared in any desired thickness, from 2/1000 inch orless up to one inch or more in thickness, all products prepared in thismanner being herein designated as paper;

The paper may be applied in any molding operation, as is well understoodby those conversant with this art, being for example disintegrated bysuitable means to form a molding mixture of general applicability. It isespecially suited for the manufacture of laminated products, thesuperposed sheets, to the desired number, bein consolidated byhot-pressure in the hy raulic press in the standard manner.

By varying the amounts of free phenol and free hexamethylenetetramine,or their equivalents, in the water solution, we are enabled to vary atwill the viscosity of the resulting mass; the less phenol andhexamethylenetetramine used, the stifi'er the mass and the less itsflow. When further plasticity is desired, it may be obtained by addingfurfural, say in the proportion of 10-15 per cent of the mass. This byreason of its aldehyde nature may also act as a hardener in the finaltransformation of the resin. 1

On account of the considerable content of phenol andhexamethylenetetramine in the water, as well as of furfural when this isemployed, it is desirable to use the water vehicle over and over,keeping a simple analytical control of the solution. By reason of thelow vapor tension of phenol, furfural and hexamethylenetetramine, andbecause of the fact that the beating and paper-laying operations may becarried out at about room temperatures, there is practically no'loss ofthese materials by evaporation.

It will be understood that as the wet paper leaves the screens its watercontent is charged with phenol and hexamethylenetetramine, as well aswith furfural", if used; and since these components, or their reactionproducts, are left as a residue in the dried paper, it is important toexercise adequate control of the water content of the paper as it leavesthe screen. The plasticity of the mass may be controlled by varying thiswater content, since the ratio of fiber is thereby controlled. As abovestated, a convenient practical rule when using ingredients in theproportions mentioned above is so to apply the vacuum that there remainsin the paper as it passes from the screens to the calender rolls,approximately one pound of water for each pound of total' solids.

Our invention is not restricted to the particular materials, proportionsand manipulations above detailed. For exam Is, the non-reactive phenolresin and the met ylene hardening agent together constitute apotentially reactive resin composition, and these components may besubstituted, wholly or in part, by potentially reactivejphenolic resinsotherwise prepared, as for example those initial phenolic condensationproducts water substantially saturated with a free phenolic body.

3. Process of making a paper product, comprising compounding a fibrousmaterial and a potentially reactive phenolic resin composition inresence of water containing a free henolic dy, and laying the resultingpu p into a sheet.

4. Process according to claim 2 in which the potentially reactivephenolic resin composition comprises a permanently fusible phenol resinand hexamethylenetetramine.

5. Process according to claim2 in which the potentially reactivephenolic resin composition comprises a non-reactive phenol resin and aplurality of hardening agents therefor.

6. Process according to claim 2 in which the potentially reactivephenolic resin composition comprises a non-reactive phenol resin,hexamethylenetetramine and furfural.

7. Process of making a paper product, comprising compounding a fibrousmaterial and a phenolic resin in presence of afree phenol and amethylene compound in aqueous solution, laying the resulting pulp mtopaper, separating from the paper a controlled proportion of the aqueoussolution, and utihzin said solution in a repetition of the pulp-ma ingprocess. I

8. Process comprising compounding in presence of water a fibrousmaterial, and a potentially reactive henolic resin compositioncomprising fur ml.

9. A paper product comprising in sheet form a fibrous material, and apotentially reactive phenolic resin composition comprising anon-reactive phenol resin, a free phenol, and a methylene hardeningagent. 10. A aper product comprising in sheet form a brous material, anda potentially reactive phenolic resin composition comprising anon-reactive henol resin, 2. free phenol, and a methy enc hardeningagent. said hardening agent proportioned to react with the free phenoland the phenol resin. 11. A paper product comprising in sheet form afibrous material, and apotentially reactive phenolic resin compositioncomprising a non-reactive phenol resin and a hardemng agent thereforincluding furfural.

' 12. A' fpaper product comprising in sheet form a brous material, and apotentially reactive phenolic resin composition comprisa non-reactivephenol resin and a hardenmg agent therefor includinghexamethylenetetramineand furfural.

13. Process of making a laminated product, consisting in superposing aplurality of sheets each comprising a fibrous material, a I

non-reactive plhenol resin, free phenol, and a methylene ardening agent;and uniting and consolidating the sheets by a hot-pressing operation.

14. Process of making a laminated product, consisting in superposing apluralit of sheets each comprising a fibrous materia a non-reactivephenol resin, and a hardening agent comprising furfural; and uniting andconsolidating the sheets by a hot-pressing operation.

15. Process of making a laminated product, consisting in superposingaplurality of sheets each com rising a fibrous material, a non-reactivep enol resin, and a hardening agent comprising hexamethylenetetramineand furfural; and uniting and consolidating the sheets by a hot-pressingoperation.

In testimony whereof, we aflix our signatures.

LAWRENCE V. REDMAN. HAROLD C. CHEETHAM.

